This proposal is for a continuation of the study entitled "Epidemiology of Migraine Headache" now in its third and final year. In the last two years a substantial body of data has been collected from four related activities: two clinical validation studies of survey instruments; a population survey of 10,169 subjects (94% response rate) 12 to 29 years of age from Washington County; a follow-up survey of 4,953 subjects (91.5% response rate); and a daily study of reliable female subjects reporting with classical migraine symptoms. Before proposing and initiating new data collection efforts we believe it is prudent to carefully and thoroughly analyze this unique and rich database. While data will be analyzed in this third year of the current study, this time frame is simply too short to address the numerous methodologic and substantive issues which can be addressed from the data collected to date. Thus, in this continuation period the primary objective is to analyze the data collected focusing on six topics: issues related to the definition and identification of a case; assessment of the validity of the survey instrument, subject repeatability, and clinician reliability; descriptive epidemiology; identification of precipitators of migraine attacks; an assessment of medical conditions associated with migraine; and a detailed description of medical care and medication use for headache and migraine. Finally, we propose to develop and validate a survey instrument specific to pediatric populations.